DESCRIPTION: Approximately 40 million people worldwide are infected with human immunodeficiency virus. According to the CDC estimates, 1,144,500 people aged 13 years and older are living with HIV infection in the USA, with ~180,900 (15.8%) others infected but undiagnosed. The advent of combination antiretroviral therapy (cART; also known as highly active antiretroviral therapies, HAART) has transformed AIDS from a fatal illness into a chronic and manageable condition. Despite the success of cART, high prevalence of HIV-associated neurocognitive disorders (HAND) poses a major challenge for the society. It is estimated that 30-50% of individuals with HIV suffer from HAND, and approximately 350,000-575,000 cases in the United States alone HAND persist after cART likely due to the HIV infected microglia and macrophage reservoirs in the central nervous system and variable penetration of anti-retroviral drugs across the blood brain barrier. Additional factors such as CNS toxicity of cART, the aging of the brain, hepatitis C co-infection and substance abuse are known to exacerbate the symptoms of HAND. Methamphetamine (METH) is a psychostimulant drug that is chronically abused by an estimated 25 million people in the world. METH users exhibit an array of health complications ranging from agitation, anxiety, hypertension, psychosis and deficits in memory, attention and executive functions. Moreover, evidence suggests that METH can lead to neuroinflammation and neurodegeneration including loss of dopamine transporters, loss of serotonin transporters, increased dopamine levels, breakdown of the blood brain barrier. HAND and METH drug abuse are major health problems with huge socioeconomical burdens on society. Molecular mechanisms of HAND and METH are not well understood, partly due to the lack of physiologically relevant human model systems. Proposed work will develop pluripotent stem cell based cerebral organoid models and employ multidisciplinary approaches to investigate novel regulatory non-coding RNAs and epigenetics mechanisms, a nascent area in biology, of brain injury caused by HAND/METH. Because of their ability to self-organize and recapitulate many regenerative events seen in vivo, organoids present a human relevant, easily accessible, scalable model for disease pathogenesis and drug testing. Since we are able to control the microenvironment of organoid formation and maintenance, brain functions under various human conditions related to development, aging, and cART treatments can be studied. Results will be correlated with patients' data and drugs will be screened to rescue synaptic defects caused by HIV and METH.